@@ -270,7 +270,7 @@ While most materials have $R_\mathrm{H}<0$, interestingly some materials are fou
1. How does the resistance of a purely 2D material depend on its size?
2. Check that the units of mobility and the Hall coefficient are correct.
(As you should always do!)
3. Explain why the scattering rates due to different types of scattering events add up in a reciprocal way.
3. Explain why the scattering times due to different types of scattering events add up in a reciprocal way.
### Exercise 1: Extracting quantities from basic Hall measurements
We apply a magnetic field $\bf B$ along the $z$-direction to a planar (two-dimensional) sample that sits in the $xy$ plane. The sample has width $W$ in the $y$-direction, length $L$ in the $x$-direction and we apply a current $I$ along the $x$-direction.
